1. Field of the Invention
This invention relates to a multiple contact electrical connector, and in particular to an improved High Speed Serial Data Connector (HSSDC) system made up of a modular plug and a receptacle having a polarization slot and a ferrite block filter.
2. Description of Related Art
The HSSDC system was developed to carry data over Ethernet connections at full duplex rates of up to four Gigabits per second, over extended cable lengths of up to ten kilometers. Although not yet subject to a formal IEEE standard, the IEEE draft proposal calls for eight signal lines and, in the case of extended length cable connections, an equalizer board connected between the contacts of the plug connector and corresponding contacts of the cable.
In general, the HSSDC connector design is similar to other network cable connector designs, but the presence of an equalizer board in the plug connector, and the relative high data rates of the proposed HSSDC standard, present a number of new problems. Although the problems are of particular concern with respect to HSSDC connectors, however, those skilled in the art will appreciate that the solutions to the problems may also have applicability to other types of connectors, and in particular to other high speed multiple contact data cable connectors.
The first problem is the difficulty in assembling the contacts of the plug connector to the equalizer board. Currently, both the connector contacts and cable conductors must be soldered to the equalizer board before placement of the entire assembly in the connector housing. As a result special handling of the cable and board is required, greatly complicating the manufacturing process. While modular designs, including modular designs utilizing solderless contact arrangements, have previously been proposed, the prior designs have either pre-positioned the connector contacts in the module, as is common in the case of RJ contacts, or provided a separate circuit board module for various filter components, as in the case of SCSI or RJ connectors. Neither of these two solutions is suitable for use in an HSSDC connector system because of the configuration of the contacts which, unlike RJ contacts, extend generally horizontally from the equalizer board, leaving them vulnerable to damage during assembly, and because of the design of the connector housing which, as a result of the high data rates, must completely enclose the equalizer board, thereby making post assembly termination of the cable to the circuit board impractical.
The second problem is that current assembly techniques require, in the case of connectors that do not include an equalizer board, termination of the connector contacts directly to the cable contacts before insertion into the connector, which requires a separate assembly line. Even if a conventional modular design could be used for such connectors, the problem would remain that separate assembly procedures or different modules are required for equalized and non-equalized connectors.
The third problem is the problem of polarization of the HSSDC system. Because of the wide variety of devices that could use HSSDC type connections, it is possible that devices could be cross-connected. It would thus be desirable to include a way to prevent otherwise identical HSSDC plugs from being plugged into the same receptacle.
Finally, the fourth problem involves the general problem of shielding and filtering the contacts. While the HSSDC cable, plug, and receptacle are all shielded against radio frequency (RF) interference, the currently proposed connector design makes no allowance for filtering out spurious signals that might result from electromagnetic interference (EMI), which can be significant due to the lengths of cable involved. Because of the unique configuration of the HSSDC system connectors, the advantages of placing an EMI filter within the HSSDC format connector have not previously been recognized, even though EMI filter arrangements are well known in the context of RJ, SCSI, and other less well-shielded cable/connector systems. In addition, conventional filtering arrangements often add significantly to the cost of assembly because of the small size of the filters and the need to terminate them to individual contacts.
It is accordingly a first objective of the invention to provide a high speed connector system including a plug connector made up of a housing, a plurality of contacts, and a circuit board connected to the contacts, in which the circuit board and contacts may be connected to each other and assembled to the connector using a modular design that does not require any pre-soldering or pre-termination of the contacts to the equalizer board.
It is a second objective of the invention to provide a high speed connector arrangement having a modular snap-together design that permits the printed circuit board to be replaced, so that the same connector plug housing can be used for applications that require equalization circuitry and also for applications that do not require equalization circuitry.
It is a third objective of the invention to provide an HSSDC connector system that includes EMI filtering and polarization features that allow plugs to be keyed to specific receptacles.
These objectives are achieved, in accordance with the principles of a preferred embodiment of the invention, by providing an electrical plug connector that includes two separate modules, one of which is an electrical contact module that plugs into the housing, and the other of which is a board that is also latched in the housing upon insertion of the board, the contacts of the electrical contact module being arranged to engage terminals of the circuit board upon insertion of the respective modules into the connector housing.
In an especially preferred embodiment of the invention, the plug connector housing, contact module, and circuit board include first complementary interengaging structures arranged to guide the contact module and circuit board into their final positions in the housing, second complementary interengaging structures arranged to latch the contact module in its final position, and third complementary interengaging structures arranged to latch the circuit board in its final position. The first interengaging structures preferably include a track extending along a sidewall of the housing, and a rib extending laterally from the contact module and arranged to fit within the track, while the second interengaging structures preferably include a latch arm on the housing extending rearwardly relative to the direction of insertion of the contact module into the housing, the latch arm on the housing having a downwardly extending projection, and a notch at a trailing side of the rib extending laterally from the contact module, the projection extending into the notch to latch the contact module in its final position. The third interengaging structures preferably include a forwardly extending latch arm on the housing, the latch arm of the third interengaging structures including a projection extending laterally into the path of insertion of the contact module into the housing, and a notch in a side of the circuit board, the projection entering the notch to latch the circuit board into the housing following latching of the contact module into the housing, at which time contacts of the contact module engage terminals on the circuit board to complete interconnection of the contacts with circuitry on the circuit board.
According to the preferred embodiment of the invention, the inclusion of complementary interengaging structures for guiding and latching both the contact module and the circuit board allows the connector to be completed by simply snapping the various parts together. Furthermore, the modular design of the preferred plug connector has the advantage that, if an equalization circuit is not required for a particular connector implementation, the printed circuit board having equalization circuitry can simply be replaced by a printed circuit board with traces that directly connect terminals on one side of the board with terminals on the other side of the board, without having to change the connector assembly procedure.
The objectives of the invention are further achieved, in accordance with the preferred embodiment of the invention, by including polarizing structures on the plug, and corresponding slots in the receptacle, the dimensions of the respective plug structures and receptacle slots serving to key the plug to the receptacle.
Finally, the objectives of the invention are also further achieved in accordance with the preferred embodiment of the invention by including in the receptacle structures that allows a filter block to be easily snapped into the receptacle housing, the receptacle contacts being inserted through an opening in the filter block so that the filter block surrounds the receptacle contacts and thereby provides EMI filtering.
Although the illustrated connector is an HSSDC connector, and some of the features of the invention involve considerations unique to HSSDC connectors, those skilled in the art will appreciate that other features of the invention, such as the modular construction, may have wider applicability, and in particular applicability to high speed data connectors other than those specifically described in the HSSDC draft protocol and previous HSSDC connector proposals.